1. Field of the Invention
The present invention relates to a mount for an optical element, and more particularly, to such a mount which can be adjusted to accurately position an optical element in optical apparatus.
2. State of the Prior Art
Optical elements must be very accurately positioned in certain types of apparatus such as apparatus using lasers as a light source. Mounts for the optical elements must be adjustable in order to position the element relative to a laser beam and to compensate for changes in the optical system during use of the apparatus. The elements must also be capable of withstanding vibration and shock without moving from an adjusted position, and thus, the mounts for the elements must include means for locking the optical elements in an adjusted position without inducing distortion or strain in the elements. One of the main problems in prior-art mounts for optical elements is that the mounts cannot be easily adjusted to a precise position. A further problem with known mounts is that it is difficult to maintain the mounts in an adjusted position.
In U.S. Pat. No. 4,171,902, there is shown a mount for an optical element in which a mirror can be pivoted about a horizontal axis to effect adjustment of a beam in one direction and about a vertical axis to effect adjustment in a second direction. Each of the adjustments is made by means of a screw which is operative to pivot the mirror against a spring force which biases the mirror in one direction of rotation. A problem with this mount is that the adjustments about both the horizontal and vertical axes are relatively coarse adjustments, and thus, even after several iterations, it is difficult to obtain a precise adjustment of an output beam.